In general, various safety devices for protecting passengers are provided in a vehicle so as to prepare for an unexpected situation that may occur at uncertain moments, and as the representative safety devices, an internal airbag for protecting the passenger and an external airbag for protecting a person colliding with the vehicle are installed in the vehicle.
However, the airbags do not sufficiently absorb impact energy because of an instantaneous deployment, and as a result, the passenger or the person colliding with the vehicle may be greatly injured.
Therefore, in order to absorb impact energy, the airbag has a structure in which an active vent concept of the existing airbag is applied, and particularly, in the case of a fellow passenger seat, vents such as a low risk deployment (LRD) vent, a general vent, and an active vent are installed together in a single side panel in order to satisfy marketability/performance set forth in the regulation. Particularly, the active vent refers to a device that adjusts internal pressure of an airbag of a front passenger seat when the airbag is deployed, and has structural characteristics of being opened and closed based on each purpose or deployment time.
FIG. 1 relates to an external airbag 10, and illustrates, as drawings, contact models in which a person collides with the vehicle at the front of the vehicle in various collision modes. FIGS. 1A to 1C each illustrates a model of collision with a stationary wall, a model of collision with a pole, and an offset collision. Vehicle collisions may occur in various manners in addition to the aforementioned modes, but the above three collision modes are generally representative of the various manners.
The active vent is opened when internal pressure of an airbag cushion is a predetermined value or more so as to induce a variation in internal pressure of the airbag cushion. In the active vent, a tether releasing structure is a device that forcibly opens the vent, and a separate explosive device is additionally provided at a cushion retainer.
Here, there is a problem in that when the active vent of a passenger airbag is applied to the external airbag, component cost is increased, and an assembly process is complicated.
In addition, there is a problem in that energy, which is transferred from a collision body, is not sufficiently absorbed due to damage to the airbag cushion and an undesirable increase in pressure at the time of a collision mode test as illustrated in FIG. 1.